用水合物储存氧气的计算化学模拟研究

Computational Chemistry Modeling of the Oxygen Storage in Clathrate Hydrates

【目的】用水合物在常温常压下能够储存氧气，在清洁能源、军事、航天、环境和生态保护等方面都有重大潜在应用，本文主要探讨水合物储氧的最佳比例和稳定性。【方法】在由20个水分子组成的正十二面体水合物512结构单元中分别放置1～3个氧分子，用量子化学方法优化氧分子簇（O2，2O2，3O2）与水合物512结构单元的作用结构，并计算水合物稳定能。【结果】在边长为2．82的水合物512结构单元中放置1个和2个氧分子时得到吸引的稳定能；当储存3个氧分子时水合物单元与氧分子簇间的稳定能转为排斥。【结论】当边长为2．82时，在水合物512结构单元中最多可以存储2个氧分子。氧分子从水合物512结构单元中逃逸的势垒高达~200 kJ／mol，远高于氢分子的逃逸势垒~80 kJ／mol。

Objective]Storage of oxygen molecules （O2 ）in clathrate hydrate at ambirent condi-tion has many potential applications,such as clean energy,environment and ecology protection, shuttle,space rocket,submarine and so on.[Methods]The clathrate hydrate of oxygen mole-cules is studied by using quantum chemical methods Hartree-Fock,B3LYP and MP2.[Results]When 1 or 2 oxygen molecules are included in the 512 hydrate cell with side length 2.82,the stable energy is atractive.When 3 oxygen molecules are trapped in the 5 12 cell,the stable energy turns to repulsive.[Conclusion]When the side length is 2.82,at most 2 oxygen molecules can be stored in a 512 hydrate cell.The escaping energy barrier of oxygen molecule is 200 kJ/mol, which is much higher than the escaping energy barrier 74 kJ/mol of hydrogen molecules.